Sensitizing of photographic silver chloride, chloro-bromide, and chloro-bromo-iodideemulsions



Patented Dec. 15, 1942 UNITED STATES PATENT OFFICE 2,304,981 SENSITIZING F PHOTOGRAPHIG SILVER CHLORIDE,

CHLORO BROMIDE,

AND

,CHLORO-BB-OMO-IODIDE EMULSIONS Gustav Wilmanns, Wolfen, Kreis Bitterield, Germany, assignor to General Aniline 8; Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application February 14, 1940,81:-

rial No. 318,834. In Germany February 8,

1939 3 Claims.

This invention relates to sensitizing photographic silver chloride, chloro-bromide and chicro-bromo-iodide emulsions. 2 Many polymethine dyestuffs, the polymethine chain of which is connected with the nitrogen atom of a primary or secondary amine, have been known up to now,

but were nearly exclusively used as intermediate products for the synthesis of cyanine dyestufis.

This class of dyestuffs was formerly believed not [onn-cmon-omcn-cmnn-o] Br possess weak sensitizing qualities. I According to the author the blue' sensitivityof the emulsion is greatly reduced thereby.

It is an object of the invention to provide new and useful sensitizing dyes and silver chloride, chloro-bromide and chloro-bromo-iodide emulsions with improved sensitizing properties.

Further objects will become apparent from the detailed specification following hereinafter.

According to this invention it was found that polymethine dyestuffs of this group sensitize most advantageously photographic emulsions of silver chloride, chloro-bromide or chloro-bromo-iodide, if they contain at least on one side of the methine chain the dihydro-u-methyl-indole ring directly linked to the nitrogen atom. The benzene ring of this dihydro-a-methyl-indole may contain the usual substituents known in cyanine dyestuiI chemistry, such as alkyl, alkoxy or amino groups. One or both hydrogen atoms of the group of the dihydro-a-methyl-indole ring may be substituted by the methyl or ethyl radical.

The other side of the methine chain of these dyestufis may either contain the dihydro-a-methyl-indole ring,'linked-in the same wayflirectly to the nitrogen atom, or be connected with a nitrogenous heterocyclic radical without direct linkage to the nitfogen atom. As nitrogenous heterocyclic radicals all heterocyclic ring systems known in cyanine dyestuff chemistry are useful, which for instance may contain the following radicals: thiazole, selenazo1e, thiazoline, selenazoline, oxazole, oxazoline, quinoline, quinaldine, lepidine, indoline, benzimidazole, rhodanine. These ring systems may be substituted in the usual manner. The azoles for instance may be substituted with the phenyl-, phenylene-, naphthylene radical. The dyestufis are of the In these formulas 11. means an odd number between 1 and 9 (Formula I and III), an even number between 2 and 6 (Formula II). In all formulas amino group.

The dyestuffs are prepared according to known processes or by methods analogous to known processes. The dyestuffs according to Formula I are prepared by condensation of the dihydroa-methyl-indole with propargyl-aldehyde-acetal or with dinitro-phenyl-pyridinium-ch1oride. The dyestuffs according to Formula II are prepared either by condensation of dyestuifs described in Formula I with the 2-alkyl-quaternary salts of the respective nitrogenous hetero bases in the ti-aldehydes and connecting them with the 2-alkyl-quaternary. salts of the heterocyclic bases.

The dyestuffs according to Formula III are pre- I pared by condensation of the respective u-aldehydes with rhodanines or their equivalents.

The dyestuffs are partly described in U. S. patent application Ser. No. 172,775, filed November 4, 1937, and also in German Patents Nos. 218,904 and 218,616.'

The dyestuffs are added in the usual manner in normal concentrations directly to the emulsion or applied in a bathing process. They may be mixed with each other or applied in mixture with other known cyanine dyestuifs. 1

The present invention is described in the following examples:

Example I A dyestufl of the following formula CH: Hi Inc-cl: lid-cm has an absorption maximum at about 130 m and a sensitizing maximum (AgCl) at 460 m The product is prepared according to the method of Claisen (Ber. 36,3667), from propargylaldehyde acetal, dihydro-a-methylindole, hydrochloric acid.

Example 11 A dyestuif of the following formula Ham] has an absorption maximum at 525 ml and a sensitizing maximum (AgCl) at 555 mu.

Preparation: 2.6 grams dihydro-u-methyli'ndole+2,8 grams dinitrophenyl-pyridinium-chloride+10 cc. alcohol are boiled for minutes. Intense red-coloring appears. Then 1 cc. 70% perchloric acid in 5 cc. alcohol (ice-cold) is added and the reaction product cooled to room-temperature. After scratching with a glass rod formation of crystals begins. At low temperature the product is sucked off and washed with alcohol and ether. It is a red powder.

Example III 7 A dyestuff of the following formula A dye of the following formula (kills has an absorption maximum in methanol at 620 m and a. sensitizing maximum (A361) at 650 mu.

mthylindole-N-pentadienal and 2-methyl-benzthiazole-ethyl-iodide with pyridine and acetic anhydrlde.

Example V A dyestufi of the following formula CH: Bicen O T \NCH=CH-CH=CH N 010. zHl

has an absorption maximum in methanol at 530 maand a sensitizing maximum (AgUl) at 560 mp.

The product is prepared from dihydro-omethylindole-N-propenal and 2-methyl-5-diethyl-aminobenzoxazole-ethyl-iodide with pyridine and acetic anhydride.

Example VI A dyestuif of the following formula lnc n \N-CH=OHCB=CH SCH:

N HI I IH:

has an absorption maximum in methanol at 485 mp and a sensitizing maximum (AgCl) at 515 m The product is prepared from dihydro-e-methylindole-N-propenal and 2-methyl-thiazolinemethyl-iodide with pyridine and acetic anhydride.

Example VII A dye of the following formula .HlC-(Bll has an absorption maximum in methanol at 470 ml and a sensitizing maximum (A901) at 520 my.

The product is prepared from dihydro-a-methylindole-N-propenal and N-ethyl-keto-thioketooxazolidine (Journ. prakt. Chemie, Volume 99,762, Ahlquist) with pyridine and acetic anhydride.

. Example VIII A dyestufl of the following formula mcn N-CH=CHCH=C-S has an absorption maximum in methanol at 500 my and a sensitizing maximum (AgCDat 550 i The product is prepared from dihydro-u-methylindole-N-propenal and N-ethylrhodanine with pyridine and acetic auhydride.

The product .is prepared from dihYdIO-a- I ylindole N propenal and 2-methyl-benzimidhas an absorption maximum in methanol at 570 my and a sensitizing maximum (AgCl), at 600 mu.

The product is prepared from the dyestufl of Example VIII by forming the quaternary salt with dimethylsulfate and condensing it with 2- methyl-benzthiazole-ethyl-iodide according to U. i 8. Patent application Ser. No. 237,474, filed October 28, 1938. Y

Example X A dye of the following formula CH1. m0 ':11

N-ICH=CHCH= i 3 has an absorption maximum in CHaOH at 535 0 ma and a sensitizing maximum at-about 570 ml.

The product is prepared from dihydro-a-methylindole-N-propenal and hydroxythionaphthene by condensing it with acetic anhydride.

Example XI A dyestufl of the following formula l i CHa-N mcn N-CH=CH-CH=CH I has an absorption maximum in methanol at about 500 m and a sensitizing maximum (AgCl) at 535 mp;

The product is prepared from dihYdIO-a-lllGthazole-ethyl-iodide with pyridine and piperidine.

Example XII A dyestufl of the following formula 3 in H .(iH

has an absorption maximum in methanol at about 490 m and a sensitizing maximum (AgCl) at 520 m The product is prepared from dihydro-a-methylindole-N-propenal and p-phenylene-diamine on one side of the polymethine chain a radical of Ithe following structure 7 R1 R1 CH:

and on the other side of-said chaina radical of the group consisting of H B1 Bi and =CS s ol heal N iz, x in wherein A means a member of the group consising of and a phenyiene, R1 means a member of the group consisting of hydrogen and alkyl,

R2 means alkyl,

V means a member of the group consisting of an alkyl, alkoxy, amino, and a modified amino radical, as a substituent at any place of the benzene nucleus,

X means acid radical,

Y means a member of the group consisting of oxygen, sulfur, selenium, CH=CH, C(CI-Ia) and NR2,

Z means a memberof the group consisting of oxygen, sulfur and selenium.

.2. A photographic material comprising a support and at least one silver chloride emulsion layer cast thereon, said layer containing a polymethine dyestuif as defined in claim 1.

3. A photographic material comprising a support and at least one silver halide emulsion layer cast thereon and containing silver chloride, said layer containing a dyestuif of the following formula:

I om a r l mc-cn NCH=CHCH=CH in. GUSTAV WIIMANNS. 

